Secure tube coupling with automatic connection

ABSTRACT

A tube coupling including a female connector a body into which a male connector having an annular collar is inserted axially, and a connection element is provided. The connection element extends in a transverse direction within the body of the female connector. The connection element is designed to interfere mechanically with the collar during insertion of the male connector and to move transversely of its own accord towards the inside of the female connector. The connection element includes a locking hook that cooperates with a locking catch provided in the female connector. The hook goes past the catch as a result of the mechanical interference of the collar that drives axial and radial elastic deformation of the connection element. The hook locks against the catch when the connection element is fully pushed into the female connector.

This U.S. utility patent application claims the benefit of French patentapplication no. 1561186, filed Nov. 20, 2015, which is incorporatedherein by reference for all purposes.

BACKGROUND

1. Technical Field

The present invention relates to the field of tube couplings forconnecting together fluid pipes or hoses, e.g. fuel hoses for motorvehicles.

2. Related Art

Such a tube coupling for coupling fuel hoses is already known, inparticular from patent documents WO 2015/177472 and US 2012/0326435.

In the known tube coupling of US 2012/0326435, the connection elementconstitutes a retaining element for blocking the male connector inposition when it is fully pushed into the female connector, forming alock that extends transversely in the female connector behind the collarof the male connector in such as a manner as to block it axially.

The connection or retaining element comprises two tines that are spacedapart from each other, like a kind of U-shaped fork, which tines extendin a transverse direction inside the female connector, each tine havinga front face that interferes with the collar of the male connector.

The connection element is initially positioned in the female connectorin a high, pre-assembly position in which the base of the U-shapeprojects outside the female connector and the two tines of theconnection element extend substantially on either side of the maleconnector in front of its collar (considering that the front of thecollar corresponds to the front face of the collar that is furthestdownstream along the axis in the direction for inserting the maleconnector into the female connector).

When the male connector is pushed axially into the female connector, thefront face of the collar of the male connector then interferes withfront faces of the tines of the connection element, which faces areoblique relative to the axial direction and also relative to thetransverse direction. This leads to the tines of the connection elementbeing moved apart radially in elastic manner by reacting to the thrustforce exerted axially against said oblique front faces, and leads totransverse movement of the connection element in the female connector byreaction to the thrust force exerted transversely against said obliquefront faces. As they move apart radially and elastically, the elastictines accumulate retraction energy. The maximum spacing of the elastictines during the transverse movement of the connection elementcorresponds to the diameter of the collar.

During downward movement of the connection element in the femaleconnector, the tines move apart over the collar until they reach themaximum spacing, i.e. diameter of the collar. Thereafter, once thediameter has gone past and because of the energy accumulated by theelastic spacing, the tines retract with a thrust force component thatextends in the transverse direction, and the transverse movement of theconnection element continues briefly towards the inside of the femaleconnector.

This provides a coupling with automatic connection.

In that prior art tube coupling, the connection element also has astationary frame extending transversely inside the female connectorparallel to the tines of the connection element and having an elastictongue at its base that extends in oblique manner relative to the axisof the female connector.

The tongue is arranged in such a manner that while the male connector isbeing pushed axially into the female connector, the male connectorpushes the tongue so as to move it axially relative to its base. As aresult, the elastic tongue is compressed and stores energy, and afterthe elastic tines of the connection element have gone past the diameterof the collar while the connection element is moving transversely, thetongue is released and produces a thrust force on the connection elementthat tends to urge it towards the inside of the female connector alongthe transverse direction.

The connection element is then in its low, retaining position in whichit forms a lock preventing axial movement of the male connector in thefemale connector. In this low position, the connection element appearsto be practically retracted into the female connector. The tongue thenmakes it possible to prolong the pushing of the connection element intothe female connector after going past the diameter of the collar of themale connector while it is moving transversely.

That known tube coupling nevertheless presents several drawbacks.

Firstly, it requires a plurality of separate parts that interact withone another in order to retain or block the male connector in the femaleconnector and move the connection element automatically towards theinside of the female connector.

Those various parts need to be mutually coordinated in dynamic andcomplex manner. They also increase the costs of fabricating the tubecoupling. That tube coupling also presents a body with large amounts ofperforation, thereby making it less robust.

Thereafter, the stroke of the connection element after it has gone pastthe collar, depends on the magnitude of the deformation of the tongue,and in practice its stroke is relatively small because the parts areminiaturized.

As a result, the spacing between the high, pre-assembly position and thelow position of the connection element is small, and this difference isdifficult to perceive, whether visually or by touch.

Furthermore, it is known that in existing tube couplings, when theconnection element is in the low position in the female connector, thetines are subjected to mechanical stresses that persist, thereby leadingto wear of the element, and in the event of the tube coupling beingheated, damage by creep is also possible.

Finally, tube couplings need to be made safer, since it is known that bypulling axially on the male connector while removing the lock, it ispossible to disconnect the male connector from the female connector.

SUMMARY

The object of the invention is thus to mitigate the above-mentioneddrawbacks.

To this end, the invention provides a tube coupling comprising a femaleconnector having a body defining an orifice into which a male connectorhaving an annular collar is to be inserted along an axial direction, anda connection element that extends along a transverse direction in arecess in the body of the female connector and that is designed to bedeformed elastically radially towards the outside of the femaleconnector by mechanical interference with the collar during theinsertion of the male connector into the female connector and, inreaction to the radial elastic deformation, to move of its own accordalong the transverse direction towards the inside of the femaleconnector, the connection element comprising at least one locking hookthat cooperates with a locking catch provided in the body of the femaleconnector, the hook closing on the catch in a locking position when theconnection element is fully pushed into the body of the femaleconnector, the coupling being characterized in that the connectionelement and said body of the female connector are designed so that,during the mechanical interference, the locking hook is initiallyprojected axially into the body of the female connector before theconnection element is deformed radially in such a manner that inreaction to the axial and elastic deformation of the connection element,the hook goes around the locking catch in order to reach the closureposition on the locking catch.

The coupling may present the following features:

-   -   the connection element is in the form of two forks, with a first        U-shaped fork forming a lock for the collar and a second        U-shaped fork forming a yoke, the forks being connected together        at the bases of the U-shapes, the second U-shaped fork having        two branches, each provided with a locking hook having its        opening facing radially;    -   in a partially pushed-in position of the connection element into        the body of the female connector, the opening of each hook is        located above a locking catch that forms an abutment for the        connection element, and in the recess of the body of the female        connector each catch is arranged in a clearance zone in which        each hook moves axially and goes around the catch;    -   each hook of the connection element is provided with a retaining        finger that prevents the connection element from moving        transversely in the clearance zone inside the recess of the        female connector;    -   the front interference face of each branch is formed by an        oblique surface that slopes relative to the axial direction and        that is arranged below the middle of the axial orifice of the        female connector in order to interfere with the collar of the        male connector;    -   each branch of the connection element has a back face opposite        from the interference front face, which back face is provided        with a peg whereby the connection element bears against the body        of the female connector in order to force the branch to twist        under the effect of the mechanical interference of the male        connector against the connection element;    -   the connection element, when it is fully pushed into the recess        of the female connector, is flush with the outside surface of        the body of the female connector, and in this position it masks        a visual indicator for verifying proper assembly that is applied        to the connection element; and    -   the coupling further comprises a clip designed to be inserted in        the connection element when the connection element is fully        inserted in the body of the female connector, the clip serving        as an indicator for verifying that the coupling is properly        assembled.

The idea is thus to transform effectively the energy that is released bythe connection element on retracting elastically both radially andaxially into a thrust force that is oriented and controlled in thetransverse travel direction of the connection element towards the insideof the female connector, and to lock the connection element in securemanner to the female connector.

With the arrangement described herein, it is possible for the connectionelement to have a position difference between a high, pre-assemblyposition and a low, locking position that is large enough to constitutea reliable indicator that can be inspected visually or by touch in orderto discover whether the male connector is fully coupled in the femaleconnector.

Furthermore, the arrangement may be implemented in a female connectorbody that remains relatively closed (i.e. perforated little) thus makingit possible to reduce the effects of contaminants, such as dust,becoming deposited inside the female connector and also increasing therobustness of the body.

Other characteristics, advantages, and details of the present inventionappear on reading the following description of an embodiment of theinvention given by way of non-limiting illustration, the descriptionbeing made with reference to the drawings summarized below.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be better understood and other advantagesappear on reading the following description and the accompanyingdrawings, in which:

FIGS. 1 and 2 are two diagrammatic exploded views of the tube couplingcomprising a female connector, a ring internal to the female connector,a connection element, and also showing a male connector in FIG. 1 ;

FIGS. 3A and 3B are respectively a profile view and an end view in twodifferent cross-sections showing the tube coupling in a pre-assemblyposition;

FIGS. 4A and 4B are respectively a profile view and an end view incross-section of the tube coupling in a first state of mechanicalinterference with the male connector, and FIG. 4C is an enlargement of aportion of FIG. 4A;

FIGS. 5A and 5B are respectively a profile view and an end view in twodifferent cross-section planes of the tube coupling in a secondmechanical interference state with the male connector;

FIGS. 6A and 6B are respectively a profile view and an end view in twocross-section planes showing the tube coupling in a first intermediatestate while lowering the connection element into the female connector;

FIGS. 7A and 7B are respectively a profile view and an end view in twocross-section planes showing the tube coupling in a second intermediatestate while lowering the connection element into the female connector;

FIGS. 8A and 8B are respectively a profile view and an end view in twocross-section planes showing the connected tube coupling;

FIGS. 9A and 9B are respectively a profile view and an end view incross-section of the tube coupling in a pre-assembly position in aparticular embodiment having a clip as an indicator of proper assembly;

FIGS. 10A and 10B are respectively a profile view and an end view incross-section view of the connected tube coupling showing the clip in ahigh position in a particular embodiment; and

FIGS. 11A and 11B are respectively a profile view and an end view incross-section of the connected tube coupling in a low position in aparticular embodiment.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

FIGS. 1 and 2 are exploded views of the various portions making up thetube coupling 1. The tube coupling 1 comprises a female tubularconnection endpiece (female connector) 2 made up of two portions in thisexample, comprising a main body 3 of tubular shape that extends along anaxial direction A and that is provided with an axial opening 4, and aring 5 that is axially engageable in the opening 4 of the main body 3.

It should be understood that a female endpiece made integrally as asingle part is also possible.

In the tube coupling 1, a male tubular connection endpiece (maleconnector) 6 is designed to be inserted axially in the female connector2, specifically in the ring 5 in this example.

The male connector 6 is in the form of an elongate cylindrical tube andit presents an annular collar on its circular periphery, with thediameter of the annular collar 7 being slightly smaller than the insidediameter of the ring 5.

As can also be seen in FIG. 1 , the body 3 of the female connector 2presents a shaped inside recess 8 showing a radial opening in its topthat forms a kind of slideway into which a connection element 10 can beinserted transversely and slide. In its portion situated below themiddle of the axial opening 4, the inside recess 8 presents twoclearance zones 11 arranged symmetrically in the form of radial slotsprovided in the annular peripheral surface of the female connector 2.These radial slots enable branches (described below) of the connectionelement 10 to splay apart radially inside the body of the femaleconnector 2.

As can be seen in FIG. 2 , in the bottom portion 3 of the femaleconnector 2, the clearance zone 11 presents an axially-arranged lockingcatch 12 and an empty space 13 adjacent to the catch 12. Another catch12 with an empty space 13 that are not visible in the figure arearranged in another clearance zone that is symmetrical to the clearancezone 11 that can be seen in FIG. 2 .

The locking catch 12 may be rectangular in shape, however it may also bean oblique surface as shown that slopes relative to the transversedirection in which the connection element 10 is inserted and that actsas a ramp for the sliding of the connection element 10.

On its outer circumference, the body 3 of the female connector 2 has ashoulder 112 adjacent to each catch 12 and forming a stop for theconnection element 10. In this example, the connection element 10 is inthe form of two forks, a first fork of upside-down U-shape forming alock 30, and a second fork of upside-down U-shape forming a yoke 14. Thetwo forks are connected together via the bases of the U-shape.

The first fork forming the lock 30 is designed to be placed behind thecollar 7 of the male connector 6 so as to hold it and block it in theaxial direction when the male connector 6 is fully pushed into theinside of the female connector 2. The lock 30 has two branches spacedapart from each other and extending in the transverse insertiondirection. The branches of the lock 30 are shaped so as to present aradius of curvature corresponding to the diameter of the cylindricaltube of the male connector 6. Each of the ends of the branches of thelock 30 presents a chamfer 31 extending axially and sloping towards theoutside of the lock 30. The end of each branch of the lock 30 in thevicinity of the chamfer 31 does not go beyond the middle of the axialopening 4 in the female connector 2.

The second fork presents two flexible branches 15 that are spaced apartfrom each other and that extend in the transverse insertion direction.The two branches 15 are shaped to form kinds of beams that slide in theslots of the slideway defined by the radial recess 8. Each flexiblebranch 15 presents a C-shaped locking hook 16 at its free end, with theopen side of the C-shape facing radially towards the inside of theorifice in the body 3 of the female connector 2. These two C-shapes faceeach other. More particularly, the end of each branch 15 is constitutedby the base of the C-shape of the hook 16.

Each flexible branch 15 of the connection element 10 presents a frontface that faces the collar 7 of the male connector 6 when it is engagedin the female connector 2, and referred to as the front face forinterference with the collar 7.

In its portion situated beneath the middle of the axial opening 4 in thefemale connector 2, the front face of each branch 15 includes an obliquesurface or feeler 17 that slopes relative to the axial insertiondirection of the male connector 6, that faces towards the inside of theorifice 4 of the female connector 2, and that when the connectionelement 10 is in a high, pre-assembly position inside the femaleconnector 2 serves to interfere with the front face of the collar 7 ofthe male connector 6 when it is pushed into the female connector 2.

Beside its front face, each of the hooks presents a retaining finger 18or lug on the base of its C-shape that projects axially from the frontface for a function that is explained below. The total thickness of thehook 16 and of the retaining finger 18 in the axial direction A isgreater than the empty space 13 adjacent to the catch 12.

In a particular embodiment, a peg 19 projects axially from the back faceof each flexible branch 15 of the connection element 10 from the middleportion of the C-shape of the hook 16, as can be seen in FIG. 2 . Thefunction of the pegs 19 is explained below.

As explained below, the flexible branches 15 of the connection element10 are arranged so that the connection element 10 moves of its ownaccord towards the inside of the female connector 2 in the transversedirection T as a result of a thrust force that is produced by reactionto elastic deformation of the flexible branches 15 acting axially andthen radially, as occurs when pushing the male connector 6 into thefemale connector 2.

In FIGS. 3A and 3B, the connection element 10 is in a high, pre-assemblyposition in the female connector 2. In the high, pre-assembly positionof the connection element 10, the top of the connection element 10projects from the top outside surface of the female connector 2sufficiently, e.g. by about 3 millimeters (mm) to 4 mm, to enable anoperator to distinguish reliably by visual or tactile inspection betweenthe high, pre-assembly position of the connection element 10 and a low,locking position of the connection element 10 in the female connector 2.

In this high, pre-assembly position, the flexible branches 15 are in arest position, with the opening in each hook 16 of the connectionelement 10 being located above the corresponding locking catch 12 in thebody 3 of the female connector 2, which catches constitute an abutmentfor the connection element 10. Thus, the connection element 10 cannot beinserted transversely by accident.

The sequence of movements made by the connection element 10 of its ownaccord in the female connector 2 is described below with reference toFIGS. 4 to 8 .

In FIGS. 4A, 4B, and 4C, the male connector 6 is partially inserted intothe female connector 2.

The top periphery of the collar 7 of the male connector comes intocontact with the branches of the lock 30 of the connection element 10via the chamfers 31. By pushing the male connector 6 axially into theorifice of the female connector 2, the collar 7 exerts mechanicalinterference with pressure in the axial direction against the feelers 17of the flexible branches 15 of the connection element 10. This axialthrust causes the flexible branches 15 to move axially but does notcause the branches 15 to move apart radially because the retainingfingers 18 on the front faces of the hooks 16 are still in abutmentagainst the locking catches 12 of the body 3 of the female connector 2and they prevent the connection element 10 from passing transverselyinto the clearance zones 11 inside the recess 8 of the female connector2.

The maximum axial movement of the branches 15 is obtained when the backfaces of the flexible branches 15 are axially in abutment against theinside of the body 3 of the female connector 2. In a particularembodiment in which bearing pegs 19 are arranged on the back faces ofthe branches 15, the maximum axial movement is obtained when the pegs 19come into abutment against the inside of the body 3 of the femaleconnector 2, as can be seen in the enlargement of FIG. 4C. In thisparticular configuration, the branches 15 tend to twist under the effectof the mechanical interference of the male connector 6 against theconnection element 10.

As can be seen in FIGS. 5A and 5B, the male connector 6 is pushed in alittle more into the female connector 2. The collar 7 continues to exertaxial pressure against the feelers 17, but the branches 15 are inabutment against the body 3 of the female connector 2 so they now moveapart radially and reach a maximum distance apart as can be seen in FIG.5B. In this spaced-apart configuration of the flexible branches 15, itcan be clearly be seen in FIG. 5B that the hooks 16 lie beyond thelocking catches 12, and during downward transverse movement of theconnection element 10 into the female connector 2, the hooks 16 go roundthe locking catches 12 in the clearance zone 11 of the female connector2 (in a manner described below).

By pushing the male connector 6 further into the female connector 2, thecollar 7 loses contact with the feelers 17 of the connection element 10,with the branches 15 retracting by sliding diametrically over the rearface of the collar 7. The collar 7 becomes blocked behind the branchesof the lock 30 and it is held between the retracted flexible branches15.

When the flexible branches 15 retract elastically, they move radiallytowards each other, while also retracting axially in the directionopposite to the direction for inserting the connection element 10, so asto return to their initial rest position. These two retraction movementsgenerate a thrust force on the connection element 10 so that theconnection element 10 moves transversely of its own accord in the recess8 towards the inside of the female connector 2, as shown in FIGS. 6 and7 , until it reaches a low, retention and locking position in the femaleconnector 2. In order to go round the catches 12 as mentioned above, itmust be understood that the hooks 16 perform a first movement by axialprojection and are then subjected to being spaced apart radially. Whenthe male connector 6 is fully pushed into the female connector 2, thehooks 16 return to a rest position in an axial direction, such that thehooks 16 become engaged radially against the sides of the catches 12 andthey become held by moving radially under the catches 12, with theretaining fingers 18 being received under the shoulders 112.

The low position of the connection element 10 is shown in FIGS. 8A and8B. In this low position, it can be seen that the catches 12 arereceived in the C-shape of the hooks 16. In this position, theconnection element 10 can no longer move upwards transversely in thebody 3 of the female connector 2. The male connector 6 is blockedaxially in the female connector 2. As a result of this arrangement, thetube coupling 1 is completely safe.

Furthermore, in this low, retaining position, the top of the connectionelement 10 (i.e. the bases of the U-shapes of the two forks) lie flushwith the outside surface (the top surface in the drawing) of the femaleconnector 2.

It can be understood that the mechanism for moving the connectionelement 10 transversely is totally internal within the female connector2, thereby enabling the overall size of the tube coupling 1 to bereduced.

It is also possible to provide a visual indicator in the tube coupling 1in order to verify that the male connector 6 has been pushed fully intothe female connector 2, with this being provided in the form of a markon the connection element 10 that becomes covered and thus masked whenit is inserted in the female connector 2.

The connection element 10 in the automatically-connecting safe tubecoupling 1 can be adapted to male connectors 6 having different shapesor different diameters, and also to collars 7 having different radii.

The tube coupling 1 has few separate parts and they can all be made outof plastics material, e.g. by injection molding or by 3D printing.

In a variant embodiment, as shown in FIGS. 9A to 11A, provision may bemade in the tube coupling 1 for a clip 20 that acts as an indicatorshowing two stages of assembling the coupling. In FIGS. 9A and 9B, theconnection element 10 is in its high, pre-assembly position. When themale connector 6 is properly inserted in the female connector 2, theclip 20 projects from the coupling, i.e. it is in a high position, ascan be seen in FIGS. 10A and 10B, thus making it possible for anoperator to perform first visual and/or tactile verification that thecoupling is properly assembled.

Thereafter, a second verification is performed by a second operator whoin turn observes that the clip 20 is in a projecting position and whopushes it manually into the coupling so that it is no longer in aprojecting position, i.e. so that it is in a low position, as can beseen in FIGS. 11A and 11B.

This two-stage verification makes it possible to observe that thecoupling is properly assembled and thereby limits assembly errors on anassembly line.

In this example, the clip 20 is in the form of a fork made up of twosubstantially flexible and parallel tines, as can be seen in FIGS. 9A to11B.

The tines of the clip 20 are designed to be inserted in respectivegrooves of the connection element 10 provided for this purpose in thetransverse direction T shown in FIG. 9B and prior to inserting the maleconnector 6.

Once the flexible tines of the clip 20 have been inserted, they exert apressure force on the inside profile of the female connector 2presenting unintentional withdrawal of the clip 20.

It can also be understood that while inserting the male connector 6 intothe female connector 2, the connection element 10 moves transverselytowards the inside of the female connector 2 in order to lock the maleconnector 6, while the clip 20 remains in the high position, projectingfrom the coupling. Once the male connector 6 is correctly inserted, theends of the tines of the clip 20 are positioned on the male connector 6and prevent the clip 20 from moving down into its low position withoutadditional thrust force being exerted.

It should be observed that the mechanism for lowering the connectionelement 10 does not interact with the mechanism for lowering the clip20, since the clip 20 is arranged to be pushed into its low positionmanually by an operator.

The invention claimed is:
 1. A tube coupling that is adapted to beconnected to a male connector, the tube coupling comprising: a femaleconnector having a body defining an orifice, and a male connector havingan annular collar which is designed to be inserted into the orifice ofthe female connector along an axial direction, and a connection elementthat, when inserted into said body of said female connector, extendsalong a transverse direction in a recess in said body of said femaleconnector and that is deformed elastically radially towards an outsideof said female connector by mechanical interference with said an annularcollar of a male connector during said an insertion of said the maleconnector into said female connector and, in reaction to said radialelastic deformation, springs back along said transverse directiontowards the inside of said female connector, said connection elementcomprising at least one locking hook, the at least one locking hookclosing on at least one locking catch provided in said body of saidfemale connector in a locking position when said connection element isfully inserted into said body of said female connector, wherein saidconnection element and said body of said female connector have a firstposition wherein said at least one locking hook is above said at leastone locking catch in said transverse direction and initially projectedaxially into said body of said female connector, an intermediateposition wherein said connection element is axially, radially andelastically deformed and said at least one locking hook is, in thetransverse direction, at a same level as said at least one lockingcatch, and a closure position wherein a part of said at least onelocking hook is placed below said at least one locking catch in thetransverse direction so as to prevent an upwards displacement of said atleast one locking hook in said transverse direction, wherein the tubecoupling is arranged so that said connection element and said body ofsaid female connector achieve said first position before saidintermediate position, and said connection element and said body of saidfemale connector achieve said intermediate position before said closureposition when said the male connector is inserted into said femaleconnector, wherein said connection element is in the form of two forks,with a first U-shaped fork forming a lock for said collar and a secondU-shaped fork forming a yoke, said forks being connected together atbases of the U-shapes, said second U-shaped fork having two branches,each branch provided with one of said at least one locking hookextending in the transverse direction and with an opening facingradially towards an inside of the orifice in the body of the femaleconnector, wherein a front interference face of each branch is formed byan oblique surface that slopes relative to said axial direction and thatis arranged below a middle of said axial orifice of said femaleconnector in order to interfere with the annular collar of the maleconnector.
 2. A coupling according to claim 1, wherein said connectionelement is in the form of two forks, with a first U-shaped fork forminga lock for said collar and a second U-shaped fork forming a yoke, saidforks being connected together at bases of the U-shapes, said secondU-shaped fork having two branches, each branch provided with one of saidat least one locking hook extending in the transverse direction and withan opening facing radially towards an inside of the orifice in the bodyof the female connector.
 3. A coupling according to claim 2 1, whereinbefore said connection element and said body of said female connectorachieve said intermediate position, said opening of each of said atleast one locking hook is located above a respective locking catch ofsaid at least one locking catch, and in said closure position, each ofsaid at least one locking catch forms an abutment for each of said atleast one locking hook, and in said recess of said body of said femaleconnector each of said at least one locking catch is arranged in aclearance zone configured so that each locking hook can move axiallytherein.
 4. A coupling according to claim 3, wherein each of said atleast one locking hook of said connection element is provided with aretaining finger that prevents said connection element from movingtransversely in said clearance zone inside said recess of said femaleconnector.
 5. A coupling according to claim 2, wherein a frontinterference face of each branch is formed by an oblique surface thatslopes relative to said axial direction and that is arranged below amiddle of said axial orifice of said female connector in order tointerfere with said collar of said male connector.
 6. A tube couplingaccording to claim 3, that is adapted to be connected to a maleconnector, the tube coupling comprising: a female connector having abody defining an orifice, and a connection element that, when insertedinto said body of said female connector, extends along a transversedirection in a recess in said body of said female connector and that isdeformed elastically radially towards an outside of said femaleconnector by mechanical interference with an annular collar of a maleconnector during an insertion of the male connector into said femaleconnector and, in reaction to said radial elastic deformation, springsback along said transverse direction towards the inside of said femaleconnector, said connection element comprising at least one locking hook,the at least one locking hook closing on at least one locking catchprovided in said body of said female connector in a locking positionwhen said connection element is fully inserted into said body of saidfemale connector, wherein said connection element and said body of saidfemale connector have a first position wherein said at least one lockinghook is above said at least one locking catch in said transversedirection and initially projected axially into said body of said femaleconnector, an intermediate position wherein said connection element isaxially, radially and elastically deformed and said at least one lockinghook is, in the transverse direction, at a same level as said at leastone locking catch, and a closure position wherein a part of said atleast one locking hook is placed below said at least one locking catchin the transverse direction so as to prevent an upwards displacement ofsaid at least one locking hook in said transverse direction, wherein thetube coupling is arranged so that said connection element and said bodyof said female connector achieve said first position before saidintermediate position, and said connection element and said body of saidfemale connector achieve said intermediate position before said closureposition when the male connector is inserted into said female connector,wherein said connection element is in the form of two forks, with afirst U-shaped fork forming a lock for said collar and a second U-shapedfork forming a yoke, said forks being connected together at bases of theU-shapes, said second U-shaped fork having two branches, each branchprovided with one of said at least one locking hook extending in thetransverse direction and with an opening facing radially towards aninside of the orifice in the body of the female connector, whereinbefore said connection element and said body of said female connectorachieve said intermediate position, said opening of each of said atleast one locking hook is located above a respective locking catch ofsaid at least one locking catch, and in said closure position, each ofsaid at least one locking catch forms an abutment for each of said atleast one locking hook, and in said recess of said body of said femaleconnector each of said at least one locking catch is arranged in aclearance zone configured so that each locking hook can move axiallytherein, wherein each branch of said connection element has a back faceopposite from an interference front face, which back face is providedwith a peg whereby said connection element bears against said body ofsaid female connector in order to force said branch to twist under aneffect of said the mechanical interference of said the annular collar ofthe male connector against said connection element.
 7. A couplingaccording to claim 1, wherein when said connection element is fullyinserted into said recess of said female connector, said connectionelement is flush with an outside surface of said body of said femaleconnector, and in this position said connection element masks a visualindicator for verifying proper assembly that is applied to saidconnection element.
 8. A coupling according claim 1, further comprisinga clip designed to be inserted in said connection element when saidconnection element is fully inserted in said body of said femaleconnector, said clip serving as an indicator for verifying that saidcoupling is properly assembled.
 9. A coupling according claim 1, whereinsaid connection element moves automatically inside said femaleconnector.
 10. A tube coupling that is adapted to be connected to a maleconnector, the tube coupling comprising: a female connector including abody, the body defining an axial opening and a radial opening that istransverse to the axial opening, the body including a first lockingcatch and a second locking catch within the radial opening; a connectionelement including a first flexible branch and a second flexible branch,the first flexible branch including a first locking hook at a firstterminal end thereof, and the second flexible branch including a secondlocking hook at a second terminal end thereof; wherein the connectionelement is positionable in the radial opening of the female connector ina pre-assembly position, an intermediate position, and a lockingposition; wherein, in the pre-assembly position, the first and secondlocking hooks of the connection element are positioned above the firstand second locking catches, such that movement of the connection elementinto the radial opening is obstructed by the first and second lockingcatches; wherein, in the intermediate position, the first and secondflexible branches are axially and radially deformed in response toengagement of an annular collar of a male connector with the first andsecond flexible branches, and the first and second locking hooks are, ina transverse insertion direction, at a same level as the first andsecond locking catches; wherein, in the locking position, the first andsecond locking hooks engage the first and second locking catches,respectively, to prevent displacement of the connection element from theradial opening in the body of the female connector; wherein theconnection element is operable to transition from the pre-assemblyposition to the intermediate position in response to a mechanicalinterference of the annular collar of the male connector with the firstand second flexible branches of the connection element; wherein theconnection element is further operable to transition from theintermediate position to the locking position by deflection of the firstand second flexible branches around the annular collar of the maleconnector which causes the connection element to automatically movewithin the radial recess of the female connector in the transverseinsertion direction; and wherein each of the first and second flexiblebranches includes an oblique surface that is sloped relative to an axialdirection of the female connector to interfere with the annular collarof the male connector.
 11. A tube coupling according to claim 10,wherein the connection element includes a first U-shaped fork and asecond U-shaped fork, the second U-shaped fork including the first andsecond flexible branches, the first and second U-shaped forks beingaxially offset from each other and integrally joined together.
 12. Atube coupling according to claim 10, wherein the first and secondlocking hooks of the connection element each include a retaining fingerthat prevents the connection element from moving transversely in theradial opening of the body of the female connector.
 13. A tube couplingthat is adapted to be connected to a male connector, the tube couplingcomprising: a female connector including a body, the body defining anaxial opening and a radial opening that is transverse to the axialopening, the body including a first locking catch and a second lockingcatch within the radial opening; a connection element including a firstflexible branch and a second flexible branch, the first flexible branchincluding a first locking hook at a first terminal end thereof, and thesecond flexible branch including a second locking hook at a secondterminal end thereof; wherein the connection element is positionable inthe radial opening of the female connector in a pre-assembly position,an intermediate position, and a locking position; wherein, in thepre-assembly position, the first and second locking hooks of theconnection element are positioned above the first and second lockingcatches, such that movement of the connection element into the radialopening is obstructed by the first and second locking catches; wherein,in the intermediate position, the first and second flexible branches areaxially and radially deformed in response to engagement of an annularcollar of a male connector with the first and second flexible branches,and the first and second locking hooks are, in a transverse insertiondirection, at a same level as the first and second locking catches;wherein, in the locking position, the first and second locking hooksengage the first and second locking catches, respectively, to preventdisplacement of the connection element from the radial opening in thebody of the female connector; wherein the connection element is operableto transition from the pre-assembly position to the intermediateposition in response to a mechanical interference of the annular collarof the male connector with the first and second flexible branches of theconnection element; wherein the connection element is further operableto transition from the intermediate position to the locking position bydeflection of the first and second flexible branches around the annularcollar of the male connector which causes the connection element toautomatically move within the radial recess of the female connector inthe transverse insertion direction; and wherein each of the first andsecond flexible branches includes a back face opposite of a frontinterference face, the back face including a peg whereby the connectionelement bears against an interior of the female connector in order toforce the first and second flexible branches to twist under an effect ofthe mechanical interference of the annular collar of the male connectorwith the first and second flexible branches of the connection element.14. A tube coupling according to claim 10 wherein, in the lockingposition, the connection element is flush with an outside surface of thebody of the female connector, and in this position the connectionelement masks a visual indicator for verifying proper assembly.
 15. Atube coupling that is adapted to be connected to a male connector, thetube coupling comprising: a female connector including a body, the bodydefining an axial opening and a radial opening that is transverse to theaxial opening, the body including a first locking catch and a secondlocking catch within the radial opening; a connection element includinga first flexible branch and a second flexible branch, the first flexiblebranch including a first locking hook at a first terminal end thereof,and the second flexible branch including a second locking hook at asecond terminal end thereof; wherein the connection element ispositionable in the radial opening of the female connector in apre-assembly position, an intermediate position, and a locking position;wherein, in the pre-assembly position, the first and second lockinghooks of the connection element are positioned above the first andsecond locking catches, such that movement of the connection elementinto the radial opening is obstructed by the first and second lockingcatches; wherein, in the intermediate position, the first and secondflexible branches are axially and radially deformed in response toengagement of an annular collar of a male connector with the first andsecond flexible branches, and the first and second locking hooks are, ina transverse insertion direction, at a same level as the first andsecond locking catches; wherein, in the locking position, the first andsecond locking hooks engage the first and second locking catches,respectively, to prevent displacement of the connection element from theradial opening in the body of the female connector; wherein theconnection element is operable to transition from the pre-assemblyposition to the intermediate position in response to a mechanicalinterference of the annular collar of the male connector with the firstand second flexible branches of the connection element; wherein theconnection element is further operable to transition from theintermediate position to the locking position by deflection of the firstand second flexible branches around the annular collar of the maleconnector which causes the connection element to automatically movewithin the radial recess of the female connector in the transverseinsertion direction; and further comprising a clip to be inserted in theconnection element when the connection element is in the lockingposition, the clip being an indicator for verifying that the coupling isproperly assembly.